scholarly journals Ebola virus triggers receptor tyrosine kinase-dependent signaling to promote the delivery of viral particles to entry-conducive intracellular compartments

2021 ◽  
Vol 17 (1) ◽  
pp. e1009275
Author(s):  
Corina M. Stewart ◽  
Alexandra Phan ◽  
Yuxia Bo ◽  
Nicholas D. LeBlond ◽  
Tyler K. T. Smith ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
Viral Entry ◽  
Receptor Tyrosine Kinase ◽  
Ebola Virus ◽  
Marburg Virus ◽  
Host Protein ◽  
Signaling Cascades ◽  
Viral Glycoprotein ◽  
Viral Particles

Filoviruses, such as the Ebola virus (EBOV) and Marburg virus (MARV), are causative agents of sporadic outbreaks of hemorrhagic fevers in humans. To infect cells, filoviruses are internalized via macropinocytosis and traffic through the endosomal pathway where host cathepsin-dependent cleavage of the viral glycoproteins occurs. Subsequently, the cleaved viral glycoprotein interacts with the late endosome/lysosome resident host protein, Niemann-Pick C1 (NPC1). This interaction is hypothesized to trigger viral and host membrane fusion, which results in the delivery of the viral genome into the cytoplasm and subsequent initiation of replication. Some studies suggest that EBOV viral particles activate signaling cascades and host-trafficking factors to promote their localization with host factors that are essential for entry. However, the mechanism through which these activating signals are initiated remains unknown. By screening a kinase inhibitor library, we found that receptor tyrosine kinase inhibitors potently block EBOV and MARV GP-dependent viral entry. Inhibitors of epidermal growth factor receptor (EGFR), tyrosine protein kinase Met (c-Met), and the insulin receptor (InsR)/insulin like growth factor 1 receptor (IGF1R) blocked filoviral GP-mediated entry and prevented growth of replicative EBOV in Vero cells. Furthermore, inhibitors of c-Met and InsR/IGF1R also blocked viral entry in macrophages, the primary targets of EBOV infection. Interestingly, while the c-Met and InsR/IGF1R inhibitors interfered with EBOV trafficking to NPC1, virus delivery to the receptor was not impaired in the presence of the EGFR inhibitor. Instead, we observed that the NPC1 positive compartments were phenotypically altered and rendered incompetent to permit viral entry. Despite their different mechanisms of action, all three RTK inhibitors tested inhibited virus-induced Akt activation, providing a possible explanation for how EBOV may activate signaling pathways during entry. In sum, these studies strongly suggest that receptor tyrosine kinases initiate signaling cascades essential for efficient post-internalization entry steps.

scholarly journals Comprehensive Analysis of Ebola Virus GP1 in Viral Entry

2005 ◽  
Vol 79 (8) ◽  
pp. 4793-4805 ◽  
Author(s):  
Balaji Manicassamy ◽  
Jizhen Wang ◽  
Haiqing Jiang ◽  
Lijun Rong
Keyword(s):  
Viral Entry ◽  
Ebola Virus ◽  
Binding Pocket ◽  
Marburg Virus ◽  
Pseudotyped Virus ◽  
Viral Glycoprotein ◽  
Functional Roles ◽  
Critical Residues ◽  
And Function ◽  
Expression Processing

ABSTRACT Ebola virus infection is initiated by interactions between the viral glycoprotein GP1 and its cognate receptor(s), but little is known about the structure and function of GP1 in viral entry, partly due to the concern about safety when working with the live Ebola virus and the difficulty of manipulating the RNA genome of Ebola virus. In this study, we have used a human immunodeficiency virus-based pseudotyped virus as a surrogate system to dissect the role of Ebola virus GP1 in viral entry. Analysis of more than 100 deletion and amino acid substitution mutants of GP1 with respect to protein expression, processing, viral incorporation, and viral entry has allowed us to map the region of GP1 responsible for viral entry to the N-terminal 150 residues. Furthermore, six amino acids in this region have been identified as critical residues for early events in Ebola virus entry, and among these, three are clustered and are implicated as part of a potential receptor-binding pocket. In addition, substitutions of some 30 residues in GP1 are shown to adversely affect GP1 expression, processing, and viral incorporation, suggesting that these residues are involved in the proper folding and/or overall conformation of GP. Sequence comparison of the GP1 proteins suggests that the majority of the critical residues for GP folding and viral entry identified in Ebola virus GP1 are conserved in Marburg virus. These results provide information for elucidating the structural and functional roles of the filoviral glycoproteins and for developing potential therapeutics to block viral entry.

scholarly journals A Diacylglycerol Kinase Inhibitor, R-59-022, Blocks Filovirus Internalization in Host Cells

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 206 ◽  
Author(s):  
Corina Stewart ◽  
Stephanie Dorion ◽  
Marie Ottenbrite ◽  
Nicholas LeBlond ◽  
Tyler Smith ◽  
...  
Keyword(s):  
Viral Entry ◽  
Ebola Virus ◽  
Kinase Inhibitor ◽  
Diacylglycerol Kinase ◽  
Marburg Virus ◽  
Host Cells ◽  
Dependent Manner ◽  
Viral Receptor ◽  
Viral Particles ◽  
Starting Point

Filoviruses, such as Ebola virus (EBOV) and Marburg virus, are causative agents of unpredictable outbreaks of severe hemorrhagic fevers in humans and non-human primates. For infection, filoviral particles need to be internalized and delivered to intracellular vesicles containing cathepsin proteases and the viral receptor Niemann-Pick C1. Previous studies have shown that EBOV triggers macropinocytosis of the viral particles in a glycoprotein (GP)-dependent manner, but the molecular events required for filovirus internalization remain mostly unknown. Here we report that the diacylglycerol kinase inhibitor, R-59-022, blocks EBOV GP-mediated entry into Vero cells and bone marrow-derived macrophages. Investigation of the mode of action of the inhibitor revealed that it blocked an early step in entry, more specifically, the internalization of the viral particles via macropinocytosis. Finally, R-59-022 blocked viral entry mediated by a panel of pathogenic filovirus GPs and inhibited growth of replicative Ebola virus. Taken together, our studies suggest that R-59-022 could be used as a tool to investigate macropinocytic uptake of filoviruses and could be a starting point for the development of pan-filoviral therapeutics.

scholarly journals Influence of different glycoproteins and of the virion core on SERINC5 antiviral activity

2019 ◽  
Author(s):  
William E. Diehl ◽  
Mehmet H. Guney ◽  
Pyae Phyo Kyawe ◽  
Judith M. White ◽  
Massimo Pizzato ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Antiviral Activity ◽  
Viral Entry ◽  
Ebola Virus ◽  
Endogenous Retrovirus ◽  
Marburg Virus ◽  
Human Endogenous Retrovirus ◽  
Target Cells ◽  
Viral Glycoprotein ◽  
Hiv 1

ABSTRACTHost plasma membrane protein SERINC5 is incorporated into budding retrovirus particles where it blocks subsequent entry into susceptible target cells. Three accessory proteins encoded by diverse retroviruses, HIV-1 Nef, EIAV S2, and MLV Glycogag, each independently disrupt SERINC5 antiviral activity, by redirecting SERINC5 from the site of virion assembly on the plasma membrane to an internal RAB7+ endosomal compartment. Pseudotyping retroviruses with particular glycoproteins, e.g., the vesicular stomatitis glycoprotein (VSV G), renders the infectivity of particles resistant to inhibition by virion-associated SERINC5. To better understand viral determinants for SERINC5-sensitivity, the effect of SERINC5 was assessed using HIV-1, MLV, and M-PMV virion cores, pseudotyped with glycoproteins from Arenavirus, Coronavirus, Filovirus, Rhabdovirus, Paramyxovirus, and Orthomyxovirus genera. Infectivity of particles, pseudotyped with HIV-1, amphotropic-MLV, or influenza virus glycoproteins, was decreased by SERINC5, whether the core was provided by HIV-1, MLV, or M-PMV. Particles generated by all three cores, and pseudotyped with glycoproteins from either avian leukosis virus-A, human endogenous retrovirus K (HERV-K), ecotropic-MLV, HTLV-1, Measles morbillivirus, lymphocytic choriomeningitis mammarenavirus (LCMV), Marburg virus, Ebola virus, severe acute respiratory syndrome-related coronavirus (SARS-CoV), or VSV, were insensitive to SERINC5. In contrast, particles pseudotyped with M-PMV, RD114, or rabies virus (RABV) glycoproteins were sensitive to SERINC5, but only with particular retroviral cores. Resistance to SERINC5 by particular glycoproteins did not correlate with reduced SERINC5 incorporation into particles or with the route of viral entry. These findings indicate that some non-retroviruses may be sensitive to SERINC5 and that, in addition to the viral glycoprotein, the retroviral core influences sensitivity to SERINC5.IMPORTANCEThe importance of SERINC5 for inhibition of retroviruses is underscored by convergent evolution among three non-monophyletic retroviruses, each of which encodes a structurally unrelated SERINC5 inhibitor. One of these retroviruses causes tumors in mice, a second anemia in horses, and a third causes AIDS. SERINC5 is incorporated into retrovirus particles where it blocks entry into target cells, via a mechanism that is dependent on the viral glycoprotein. Here we demonstrate that retroviruses pseudotyped with glycoproteins from several non-retroviruses are also inhibited by SERINC5, suggesting that enveloped viruses other than retroviruses may also be inhibited by SERINC5. Additionally, we found that sensitivity to SERINC5 is determined by the retrovirus core, as well as by the glycoprotein. By better understanding how SERINC5 inhibits viruses we hope to extend fundamental understanding of virus replication and of the native role of SERINC5 in cells, and perhaps to advance the development of new antiviral strategies.

Successful retreatment with erlotinib after erlotinib-related interstitial lung disease

2021 ◽  
pp. 030089162110200
Author(s):  
Haci M. Turk ◽  
Mustafa Adli ◽  
Melih Simsek ◽  
Altay Aliyev ◽  
Mehmet Besiroglu
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Interstitial Lung Disease ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Lung Disease ◽  
Receptor Tyrosine Kinase ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Epidermal Growth

Background: Epidermal growth factor receptor tyrosine kinase inhibitors are effectively being used in the treatment of non-small cell lung cancer. Although most of their adverse effects are mild to moderate, they occasionally can cause life-threatening interstitial lung disease. We aimed to present a case of lung adenocarcinoma successfully re-treated with erlotinib after recovery with effective treatment of erlotinib-induced interstitial lung disease. Case description: A 54-year-old nonsmoking woman was diagnosed with metastatic adenocarcinoma of the lung. After progression with first-line chemotherapy, erlotinib 150 mg daily was initiated. On the 45th day of erlotinib treatment, interstitial lung disease occurred and erlotinib was discontinued. Clinical improvement was achieved with dexamethasone treatment and erlotinib was re-initiated. Ten weeks after re-initiation of erlotinib, 100 mg daily partial response was observed. Conclusions: Incidence of interstitial lung disease is higher in men, smokers, and patients with pulmonary fibrosis. Interstitial lung disease radiologically causes ground-glass opacity and consolidation. The physician should quickly evaluate new respiratory symptoms in patients treated with epidermal growth factor receptor tyrosine kinase inhibitors, discontinue the epidermal growth factor receptor tyrosine kinase inhibitor treatment, and initiate corticosteroids if clinical diagnosis is interstitial lung disease.

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